The field of the present invention relates generally to apparatus and methods for folding products and more particularly, to apparatus and methods for folding products with increased alignment control at relatively high line speeds.
One known technology used to fold products as they proceed through a product manufacturing system is “blade folding”. Blade folding involves striking a discrete, moving product at a desired location with a blade to form a “bite” in the product. The bite is directed into a set of in-running conveyor belts to fold portions of the product. Examples of such blade folding apparatus and methods of their use are described in U.S. Pat. No. 4,053,150 to Lane; U.S. Pat. No. 4,519,596 to Johnson et al.; and U.S. Pat. No. 4,650,173 to Johnson et al. Various products can be folded using blade folding apparatus including disposable personal care products. Disposable personal care products are well known and include diapers, training pants, adult incontinence garments, feminine pads, bed liners, pet-care mats, dinner napkins, toweling, chair liners, etc.
One disadvantage of known blade folding technology is that the precision and repeatability of the folds in the products is dependent upon the timing of when the blade strikes the moving product as well as the traction of the in-running belts to the product bite. Plus, blade folding requires that the product is “free” when it is struck by the blade. Thus, there is a period of time in the folding process when a leading portion of the product is not held in place, and as a result, is not under direct positioning control. These features of blade folding are undesirable when precise fold positioning is needed, particularly at high speeds, such as speeds ranging from 400 products per minute to 4000 products per minute, depending on the product being folded.
Another disadvantage of blade folding is the “cudgeling effect”. That is, the bludgeoning force of the blade striking the product can result in deformed products, damaged products, poor folding alignment, poor folding repeatability, as well as other undesirable results.
Thus, there is a need for a folding apparatus and method of folding products at high speeds where the products can be folded in repeatable alignment at high speeds. There is a further need for apparatus and methods for folding products without the resulting deformation, damage and/or other undesirable effects inherent in current blade folding apparatus and methods.